st/dri, st/xorg: fix buffers that have attachements of different depth

we actually need to specify the formats for different attachements, otherwise
if the color buffer is 24bpp and the app asks for 16bpp depth buffer than
we end up fetching the depth from the drawable which is 24bpp and end up
creating the wrong depth buffer. use the new getBuffersWithFormat extension
to pass the depth correctly.
2 files changed